Dust samples recently taken from EPA’s Ariel Rios headquarters building were in many cases much higher than federal government limits for commercial buildings, documents show.

In one case, a dust sample showed lead levels 92,500 percent higher than the equivalent regulatory standard to which EPA says it is comparing results. That sample was taken from the floor of a state-of-the-art control center for responding to emergency outbreaks of toxic substances such as anthrax.

Lead is a toxic heavy metal known to cause permanent brain damage in children. Exposure to pregnant women can transfer to their unborn children. Though exposure to children is lead’s most dangerous impact, adults suffer neurological damage at high exposure levels. EPA says lead is a “probable” carcinogen.

An EPA spokeswoman referred questions to the General Services Administration (GSA), which owns EPA’s headquarters building and is running cleanup efforts. But privately, top EPA officials said the building’s occupants are safe, pointing to air samples that had lower lead levels than the dust sample. The GSA did not reply to a request for comment.

The emergency control center — which had the highest lead readings of anywhere in the building — is across the hall from a Secret Service shooting range in the basement of Ariel Rios that is suspected to be the cause of the outbreak.

Most bullets are made of lead, and commercial shooting ranges employ sophisticated air-filtering systems to control contamination.